This invention relates to rain detection apparatus and method. In particular but not exclusively, it relates to a vehicle window cleaning apparatus. It also relates to a vehicle fitted with such an apparatus.
In one known situation, it has long been desired to automatically sense the condition of a vehicle window in order to activate vehicle window cleaning apparatus. An example would be to automatically activate the wipers and/or washers of a car's window (commonly referred to as a windscreen or windshield) should the window become rained upon or should it become otherwise obscured by dust, dirt or debris.
Prior art solutions to the problem have generally used infra red sensors or sensors of the visible yellow type mounted on the appropriate window. However, these only sense the condition of a limited area of window and require close association with the window, which can cause problems should the window need replacing.
As well as cleaning of vehicle windows, it is also desirable to provide for the automatic cleaning of many other surfaces where obscuring media such as rain drops, dirt or debris on the surface would cause problems if it obscures the view through the surface. An example would be the glass or plastic lens of a headlamp or other light of a vehicle.